#!/bin/bash
#
# Developed by Fred Weinhaus 10/10/2012 .......... revised 11/25/2019
#
# ------------------------------------------------------------------------------
# 
# Licensing:
# 
# Copyright © Fred Weinhaus
# 
# My scripts are available free of charge for non-commercial use, ONLY.
# 
# For use of my scripts in commercial (for-profit) environments or 
# non-free applications, please contact me (Fred Weinhaus) for 
# licensing arrangements. My email address is fmw at alink dot net.
# 
# If you: 1) redistribute, 2) incorporate any of these scripts into other 
# free applications or 3) reprogram them in another scripting language, 
# then you must contact me for permission, especially if the result might 
# be used in a commercial or for-profit environment.
# 
# My scripts are also subject, in a subordinate manner, to the ImageMagick 
# license, which can be found at: http://www.imagemagick.org/script/license.php
# 
# ------------------------------------------------------------------------------
# 
####
#
# USAGE: meshwarp -f file [-i] [-p] infile outfile
# USAGE: meshwarp [-h or -help]
# 
# OPTIONS:
# 
# -f     file         textfile containing src and dst x,y control point pairs 
#                     and triangle vertex indices
# -i                  display information about number of src, dst and triangles
# -p                  display triangle progress
# 
###
# 
# NAME: MESHWARP 
# 
# PURPOSE: To warp an image according to a triangular mesh.
# 
# DESCRIPTION: MESHWARP warps an image according to a user supplied triangular 
# mesh. The mesh list src and dst x,y control points per line. Then a list of 
# triangle vertex indices is listed one triangle per line. This script may 
# be used to simply warp part or all of an image or to warp one image to match 
# another.
# 
# 
# ARGUMENTS: 
# 
# -f file ... FILE is a text file containing first a pair of scr and dst x,y 
# control points separated by a space. The following that is a list of 3 comma 
# separate triangle vertex indices. Vertex indices start at 0 and reference 
# the corresponding pair of src and dst x,y control points.
# 
# -i ... Enable the listing to the terminal of number of src, dst and 
# triangles extracted from the file.
# 
# -p ... Enable the listing to the terminal of the triangle numbers as the 
# triangles are processed.
# 
# Note: the script may be rather slow due to the processing of each triangle 
# one-at-a-time.
# 
# CAVEAT: No guarantee that this script will work on all platforms, 
# nor that trapping of inconsistent parameters is complete and 
# foolproof. Use At Your Own Risk. 
# 
######
# 

# set default values
info=false
progress=false
debug=false

# set directory for temporary files
dir="."    # suggestions are dir="." or dir="/tmp"

# set up functions to report Usage and Usage with Description
PROGNAME=`type $0 | awk '{print $3}'`  # search for executable on path
PROGDIR=`dirname $PROGNAME`            # extract directory of program
PROGNAME=`basename $PROGNAME`          # base name of program
usage1() 
	{
	echo >&2 ""
	echo >&2 "$PROGNAME:" "$@"
	sed >&2 -e '1,/^####/d;  /^###/g;  /^#/!q;  s/^#//;  s/^ //;  4,$p' "$PROGDIR/$PROGNAME"
	}
usage2() 
	{
	echo >&2 ""
	echo >&2 "$PROGNAME:" "$@"
	sed >&2 -e '1,/^####/d;  /^######/g;  /^#/!q;  s/^#*//;  s/^ //;  4,$p' "$PROGDIR/$PROGNAME"
	}


# function to report error messages
errMsg()
	{
	echo ""
	echo $1
	echo ""
	usage1
	exit 1
	}


# function to test for minus at start of value of second part of option 1 or 2
checkMinus()
	{
	test=`echo "$1" | grep -c '^-.*$'`   # returns 1 if match; 0 otherwise
    [ $test -eq 1 ] && errMsg "$errorMsg"
	}

# test for correct number of arguments and get values
if [ $# -eq 0 ]
	then
	# help information
   echo ""
   usage2
   exit 0
elif [ $# -gt 6 ]
	then
	errMsg "--- TOO MANY ARGUMENTS WERE PROVIDED ---"
else
	while [ $# -gt 0 ]
		do
			# get parameter values
			case "$1" in
		  -h|-help)    # help information
					   echo ""
					   usage2
					   exit 0
					   ;;
				-f)    # get  text file
					   shift  # to get the next parameter
					   # test if parameter starts with minus sign 
					   errorMsg="--- INVALID FILE SPECIFICATION ---"
					   checkMinus "$1"
					   textfile="$1"
					   ;;
				-i)    # get info
					   info=true
					   ;;
				-p)    # get progress
					   progress=true
					   ;;
				 -)    # STDIN and end of arguments
					   break
					   ;;
				-*)    # any other - argument
					   errMsg "--- UNKNOWN OPTION ---"
					   ;;
		     	 *)    # end of arguments
					   break
					   ;;
			esac
			shift   # next option
	done
	#
	# get infile and outfile
	infile="$1"
	outfile="$2"
fi


# set directory for temporary files
# tmpdir="/tmp"
tmpdir="."

dir="$tmpdir/MESHWARP.$$"

mkdir "$dir" || errMsg "--- FAILED TO CREATE TEMPORARY FILE DIRECTORY ---"
trap "rm -rf $dir;" 0
trap "rm -rf $dir; exit 1" 1 2 3 15
#trap "rm -rf $dir; exit 1" ERR


# read input image
convert -quiet "$infile" -depth 8 $dir/tmpI.mpc ||
echo  "--- FILE $infile DOES NOT EXIST OR IS NOT AN ORDINARY FILE, NOT READABLE OR HAS ZERO SIZE  ---"

# get im_version
im_version=`convert -list configure | \
	sed '/^LIB_VERSION_NUMBER */!d; s//,/;  s/,/,0/g;  s/,0*\([0-9][0-9]\)/\1/g' | head -n 1`


if [ "$im_version" -ge "07000000" ]; then
	identifying="magick identify"
else
	identifying="identify"
fi

# get image dimensions
ww=`$identifying -ping -format "%w" $dir/tmpI.mpc`
hh=`$identifying -ping -format "%h" $dir/tmpI.mpc`


# verify textfile
[ -f $textfile -a -r $textfile -a -s $textfile ] || \
	echo  "--- FILE $textfile DOES NOT EXIST OR IS NOT AN ORDINARY FILE, NOT READABLE OR HAS ZERO SIZE  ---"

# read text file into a tmpArr
i=0
while read line; do
	# replace spaces before or after commas with just the comma
	tmpArr[$i]=`echo $line | sed 's/[ ][ ]*,/,/g; s/,[ ][ ]*/,/g'`
	i=$((i+1))
done < "$textfile"

if $debug; then
	echo ${tmpArr[*]}
fi
num=${#tmpArr[*]}
if $info; then
	echo ""
	echo "num records=$num"
fi
#echo ${tmpArr[0]}
#echo ${tmpArr[125]}
echo ""

# extract scr and dst arrays
for ((i=0; i<num; i++)); do
	# note if not put "" around array it will convert all spaces to one space
	if [ `echo ${tmpArr[$i]} | wc -w` -eq 2 ]; then
		srcArr[$i]=`echo ${tmpArr[$i]} | cut -d\  -f 1`
		dstArr[$i]=`echo ${tmpArr[$i]} | cut -d\  -f 2`
	fi
done

if $debug; then
	echo ${srcArr[*]}
fi
nums=${#srcArr[*]}
if $info; then
	echo "num scr pts=$nums"
	echo ""
fi
if $debug; then
	echo ${dstArr[*]}
fi
numd=${#dstArr[*]}
if $info; then
	echo "num dst pts=$numd"
	echo ""
fi

# check if consistent number of control pts src vs dst
[ $nums -ne $numd ] && echo "--- INCONSISTENT NUMBER OF SRC AND DST CONTROL PTS ---"

# extract the triangles
j=0
for ((i=nums; i<num; i++)); do
	# note if not put "" around array it will convert all spaces to one space
	if [ `echo ${tmpArr[$i]} | wc -w` -eq 1 ]; then
		triArr[$j]=${tmpArr[$i]}
		j=$((j+1))
	fi
done
if $debug; then
	echo ${triArr[*]}
fi
numt=${#triArr[*]}
if $info; then
	echo "num triangles=$numt"
	echo ""
fi


# function to extract vertex coordinates for a given triangle
getTriangle()
	{
	# get triangle
	triangle="$1"
	v1=`echo $triangle | cut -d,  -f 1`
	v2=`echo $triangle | cut -d,  -f 2`
	v3=`echo $triangle | cut -d,  -f 3`

	# get src vertices
	s1="${srcArr[$v1]}"
	s2="${srcArr[$v2]}"
	s3="${srcArr[$v3]}"

	# get dst vertices
	d1="${dstArr[$v1]}"
	d2="${dstArr[$v2]}"
	d3="${dstArr[$v3]}"

	# compute x,y components
	s1x=`echo $s1 | cut -d, -f 1`
	s1y=`echo $s1 | cut -d, -f 2`
	s2x=`echo $s2 | cut -d, -f 1`
	s2y=`echo $s2 | cut -d, -f 2`
	s3x=`echo $s3 | cut -d, -f 1`
	s3y=`echo $s3 | cut -d, -f 2`
		
	d1x=`echo $d1 | cut -d, -f 1`
	d1y=`echo $d1 | cut -d, -f 2`
	d2x=`echo $d2 | cut -d, -f 1`
	d2y=`echo $d2 | cut -d, -f 2`
	d3x=`echo $d3 | cut -d, -f 1`
	d3y=`echo $d3 | cut -d, -f 2`

	# get min bounding box for viewport
	xmin=`convert xc: -format "%[fx:min($d1x,min($d2x,$d3x))]" info:`
	ymin=`convert xc: -format "%[fx:min($d1y,min($d2y,$d3y))]" info:`
	wd=`convert xc: -format "%[fx:max($d1x,max($d2x,$d3x)) - $xmin + 1]" info:`
	ht=`convert xc: -format "%[fx:max($d1y,max($d2y,$d3y)) - $ymin + 1]" info:`

if $debug; then
	echo ""
	echo "list triangle components"
	echo ""
	echo "v1=$v1; v2=$v2; v3=$v3"
	echo "s1=$s1; s2=$s2; s3=$s3"
	echo "d1=$d1; d2=$d2; d3=$d3"
	echo "s1=$s1x,$s1y: s2=$s2x,$s2y; s3=$s3x,$s3y"
	echo "d1=$d1x,$d1y: d2=$d2x,$d2y; d3=$d3x,$d3y"
	echo "s1=$s1x,$s1y: s2=$s2x,$s2y; s3=$s3x,$s3y"
	echo "d1=$d1x,$d1y: d2=$d2x,$d2y; d3=$d3x,$d3y"
	echo "xmin=$xmin; ymin=$ymin; wd=$wd; ht=$ht"
fi
	}

# create initially transparent background image
convert -size "${ww}x${hh}" xc:none $dir/tmpT.mpc

if $progress; then
	echo ""
	echo "Processing Triangle:"
	echo ""
fi

# loop over each triangle and create composited X and Y distortion maps
for ((i=0; i<numt; i++)); do
	# get triangle info
	getTriangle "${triArr[$i]}"
	if $progress; then
		echo "$i"
	fi
	# do affine warp and mask with triangle and composite over previous result
	# read previous iteration result (initially a fully transparent image)
	# do rectangular viewport crop on input image for a given triangle
	# apply affine warp on viewport data
	# extend the warped viewport to full image size filling with transparency (none) and roll to correct location for viewport
	# create a white triangle on black background and use that as a mask
	# composite the previous iteration image, the warped and shifted image and the triangle mask and save as next iteration result 
	convert $dir/tmpT.mpc \
		\( $dir/tmpI.mpc -define distort:viewport=${wd}x${ht}+${xmin}+${ymin} \
		-distort Affine "$s1x,$s1y $d1x,$d1y  $s2x,$s2y $d2x,$d2y  $s3x,$s3y $d3x,$d3y" \
		-background none -extent ${ww}x${hh} -roll +${xmin}+${ymin} \) \
		\( -size "${ww}x${hh}" xc:black +antialias -fill white -draw "polygon $d1 $d2 $d3" \) \
		-compose over -composite $dir/tmpT.mpc
done

# write to output
convert $dir/tmpT.mpc "$outfile"


exit 0